As Gilda used to say -- "Never Mind"

I.I.T.S. or 'It Isn't That Simple' is the rule which dominates and informs one's attempts to understand the world.

The problem with human-induced global warming is that it is fast, all but instantaneous in geological, and more importantly in evolutionary timescales. If it came into effect over a period of several tens of millions of years during which new species could evolve to replace and more than replace old ones as they became extinct, then I would have been right. As the tropical forests expanded, the new species in them would outnumber the temperate and arctic species becoming extinct because of the same climatic change.

But extinction can be quick. Evolution cannot. The timescale of human-induced climate change is in decades, not eons.

Few things that happen on earth are of any lasting effect. Mountain ranges comes and go, seas cover the land and then recede, dams block rivers for a geological instant and are then swept away, glaciers cover the land then melt.

Extinctions are an exception. Once the last condor, red-legged tree frog, smokey leopard, or blue whale bites the big one, it stays that way permanently. Extinctions are the natural course of things and are not to be feared nor even complained of -- IF and only IF they are balanced by an equal or greater rate of speciation, of the creation of new species.

That is not happening with current human-caused extinctions and it surely won't happen with global warming induced extinctions. So global warming, by my reasoning and values, actually is the catastrophe everyone says it is.